PHP implements a general method for downloading images

function getPicture($url,$pictureName){
 if ($url == "") return false;
 //Get the extension of the picture
 $info = getimagesize($url);
 $mime = $ info['mime'];
 $type = substr(strrchr($mime,'/'), 1);
 //Choose different image generation and saving functions for different image types
 switch($type){
 case 'jpeg':
 $img_create_func = 'imagecreatefromjpeg';
 $img_save_func = 'imagejpeg';
 $new_img_ext = 'jpg';
 break;
 case 'png':
 $img_create_func = 'imagecreatefrompng';
 $img_save_func = ' imagepng';
 $new_img_ext = 'png';
 break;
 case 'bmp':
 $img_create_func = 'imagecreatefrombmp';
 $img_save_func = 'imagebmp';
 $new_img_ext = 'bmp';
 break;
 case ' gif':
 $img_create_func = 'imagecreatefromgif';
 $img_save_func = 'imagegif';
 $new_img_ext = 'gif';
 break;
 case 'vnd.wap.wbmp':
 $img_create_func = 'imagecreatefromwbmp';
 $ img_save_func = 'imagewbmp';
 $new_img_ext = 'bmp';
 break;
 case 'xbm':
 $img_create_func = 'imagecreatefromxbm';
 $img_save_func = 'imagexbm';
 $new_img_ext = 'xbm';
 break;
 default:
 $img_create_func = 'imagecreatefromjpeg';
 $img_save_func = 'imagejpeg';
 $new_img_ext = 'jpg';
 }
 if ($pictureName == ""){
 $pictureName = time().". {$new_img_ext}";
 }else{
 $pictureName = $pictureName.".{$new_img_ext}";
 }
 $src_im = $img_create_func($url); //Create a new picture from url
 $img_save_func($ src_im, $pictureName); //Output file to file
 return $pictureName;
}

Download image, PHP